Michael Douglas is credited for raising awareness about the links between oral sex and oral cancer, but experts worry his disclosure could cause public panic and stigmatize the disease to the point of bringing shame to those afflicted. Or worse, prevent patients with symptoms from getting examined promptly.

Miriam Rosin, a BC Cancer Agency scientist, said the actor’s candid revelation that his throat cancer was caused by human papillomavirus (HPV), which he picked up from performing cunnilingus, is raising awareness of a growing problem around the world, and in B.C. “It’s created a lot of noise. I think it’s important to talk about this disease … but not in a headline-grabbing way, which may damage the cause by labelling it as a sexually transmitted disease,” said Rosin, who is also a Simon Fraser University professor.

Regardless, the public is finally getting the message that HPV, the most common sexually transmitted virus in the world – and the one that causes virtually all cases of cervical cancer – is accounting for the surge in throat cancers located at the back of the throat.

In B.C., if trends continue, HPV-caused throat cancers are expected to overtake cervical cancers in incidence. About 150 cases of cervical cancers are reported annually in this province. Of about 500 head and neck cancers, 115 are HPVcaused throat cancers, according to the BCCA.

Douglas’s interview with The Guardian newspaper last month was followed by an avalanche of sensational media reports that apparently gave the Hollywood celebrity a twinge of regret. Douglas’s publicist later claimed the 68-year-old meant only that oral sex and HPV were a potential cause of such cancers while not specifically referring to his own. The U.K. newspaper, however, stood by the story and released an audio of the interview to rebut Douglas’s backtracking. Excessive smoking and drinking alcohol are also risk factors for various forms of oral cancer, and when the actor was first diagnosed in 2010, he had previously blamed his cancer on many years of indulgence in those habits.

Up to 70 per cent of throat cancers are HPV-related. There are numerous places to get oral cancers – such as the lips, cheeks, gums, palate, tongue and tonsils – and while smokers and drinkers once fit the typical profile of an oral cancer patient, now, because of waning smoking prevalence, HPV infections have emerged as the dominant risk factor for throat tumours such as the one Douglas had.

Rosin said there was a whopping 300-per-cent increase in the age-adjusted incidence rate for throat cancers in B.C. between 1980 and 2010. It’s more commonly diagnosed in mid-life, and the ratio of males to females getting such cancers is three-to-one.

Earlier this year, the American Cancer Society issued a report showing the proportion of HPV-linked oral cancers has risen from 16 per cent of all oral cancers in the mid-1980s to 72 per cent two decades later.

Dr. John Hay, a radiation oncologist at the BC Cancer Agency and an expert in oral cancers, said HPV tumours are squamous cell clusters that surface in places where skin tissue is thin and delicate.

There are more than 100 strains of HPV. Some are benign, causing common skin warts, but high-risk strains cause cervical and oral cancers, vaginal and vulva cancers, penis and anus cancers, and genital warts. HPV infections and their links to cancer are a relatively new scientific area of study so there are many questions still to be answered, including whether the relatively new HPV vaccine will prevent future generations from getting throat cancers.

The Vancouver Sun has reviewed the latest research and developments to address expected curiosity on the subject.

How common is HPV?
Very. By age 25, a quarter of Canadian women are infected by it, and by age 50, about 85 per cent of sexually active people (males and females) have been exposed to it at one time or another. The vast majority of the time, the immune system knocks the virus out within a few years. In a minority of individuals, the virus persists, potentially leading to an HPV-linked cancer.

What is fuelling the rise in HPV over the past three or four decades?
Experts believe the advent of oral contraceptives. (The Pill) five decades ago unleashed sexual freedom and changes in sexual behaviours: more sexual partners and consequently more sexually transmitted infections, including HPV. Hay said before oral contraceptives came along, condoms were the common barrier method. “Condoms keep things in and they keep things out,” he said, referring to the fact that condoms can help prevent sexually transmitted infections while oral contraceptives do not.

Is the massive increase in throat cancers attributable to better detection methods or an increase in HPV infections?
Experts say they are seeing a true increase in the proportion of throat cancers caused by HPV. Hay said typical patients are 45 to 65 years old who may have been infected with HPV up to 20 years earlier.

Does oral sex really cause throat cancer?
The HPV virus is very common; nearly everyone who has sex will get it at one point or another. The HPV micro-organisms can reside in the cervix or other body canals (anus) and the virus can also be transmitted through skin contact and saliva. One Finnish study showed that HPV could even be detected in babies under one year, possibly through skin-to-skin contact during breastfeeding.

Men are more likely to get throat cancer and one theory is that there may be more HPV in vaginal fluid than other genital areas.

“We don’t well understand how oral HPV is transmitted except to know that oral sex is the most likely way of transmitting HPV to the mouth,” said Gypsyamber D’Souza, an epidemiologist and viral cancer expert from Johns Hopkins Bloomberg School of Public Health, at the recent annual meeting of the American Society of Clinical Oncology.

What are the risk factors for contracting HPV?
Studies have shown that men are three times more likely to get HPV-related throat cancers than women, but risk for both genders goes up in those with more sexual partners. Those who’ve had six or more oral sex partners over a lifetime are 8.6 times more likely to get HPV throat cancers, compared with those who have never had oral sex. HPV is more prevalent in sexually promiscuous individuals and those already carrying other sexually transmitted infections (STI). A B.C. study done on men attending a Vancouver STI clinic found that 70 per cent were HPVpositive.

What are some of the most common symptoms of throat and other oral cancers?
Hoarseness, chronic sore throat, pain or difficulty swallowing, a painless lump in the neck area, swollen lymph nodes in the neck, ear pain and mouth sores that don’t heal.

Who should get the HPV vaccine?
There are two HPV vaccines licensed for use in Canada: Gardasil and Cervarix. Neither will wipe out infections once individuals have been exposed, so it’s best to get the vaccine before becoming sexually active. B.C. research has shown that HPV is most prevalent in women under 20, suggesting that the risky period for getting infected is when females first start having sex.

Gardasil (which protects against multiple high-risk HPV strains as well as genital warts) is approved for women aged nine to 45 and males nine to 26. Health Canada approved the vaccine for girls in 2006 and for boys a few years ago. It’s part of school-based immunization programs, but the major focus of public funding is on Grade 6 girls in B.C. The series of three shots costs up to $500 if purchased at pharmacies by parents wishing to vaccinate boys or older children who missed getting vaccinated.

The vaccine is also licensed for males up to age 25. As with girls, experts recommend boys get vaccinated before they become sexually active. Only a few provinces are considering public coverage of the vaccine for males; B.C. is not one of them at this time.

Dr. Perry Kendall, chief medical health officer for B.C., said studies have not yet proven it would be cost effective to extend public funding for vaccination of boys. “Ninety-nine per cent of cervical cancers are caused by HPV, and 70 per cent of vaginal cancers,” he said, while noting that HPV is “attributable” to about twothirds of throat cancers. B.C. spends about $3 million a year on HPV vaccines and about 60 to 70 per cent of eligible girls (Grade 6 cohorts) have been vaccinated so far, but it could take decades for the vaccine to have a significant effect in reducing both cervical and oral cancers in the younger generations.

Is the vaccine safe and effective?
A Universit y of B. C. researcher Dr. Simon Dobson has called Gardasil an “excellent vaccine.” HPV-infection suppression rates range from 70 to 90 per cent, with the highest immunity response occurring in those who get the vaccine at the youngest age.

Minor side effects such as pain at the site of injection, swelling, dizziness, nausea and headache have been reported in about six per cent of subjects, according to Dr. Monika Naus of the B.C. Centre for Disease Control in a report in the BC Medical Journal. Rare, serious adverse effects – such as deaths, stroke, embolisms and seizures – have not been directly linked to the vaccine.

How can you get tested for HPV?
Doctors scrape cells from the cervix area, similar to the way specimens are collected during a Pap smear. The test is not covered by the public medical plan so private labs charge about $90. It is not possible to swab the back-of-throat area for HPV because of gag and vomit reflexes. Saliva tests are used to detect throat HPV infections only for research purposes so far.

In women and men, swabs can be taken of the anal cavity to detect pre-cancerous changes.

Is there a treatment for HPV?
There’s no treatment for the infection but there are for the serious cancers that may result from it, such as surgery, chemotherapy and radiation.

What’s the prognosis for someone who gets HPV oral cancer?
Even those who get advanced HPV-caused throat cancers, such as actor Michael Douglas, have a fiveyear survival rate of at least 80 per cent, whereas advanced non-HPV linked oral cancers – those caused by smoking and alcohol – have a survival rate about half that. Non-HPV cancers usually affect the front of the tongue, floor of the mouth, cheeks and gums, while HPV cancers tend to affect the back regions of the mouth: the base of the tongue and tonsil area.

Is there a screening program for HPV-related oral cancers?
There’s no way to screen for HPV-related throat cancers, but a B.C.-developed device called the VELscope is used by some dentists to detect abnormalities in the front parts of the oral cavity. The device utilizes special light to detect suspicious cells, but it has not yet been shown to find HPVtype cancers in the furthest reaches of the throat. The tonsil area has folds and crevices where HPV tumours can hide out. BC Cancer Agency scientists are trying to improve the imaging system for the hardto-reach sites at the back of the throat and tonsil area.

Does it take a long time for an HPV infection to arise or should you blame the last person you had sex with?
If you do get HPV, you can’t necessarily point the finger at the last individual you had sex with. HPV infections wax and wane over lifetimes so getting an HPV-linked cancer may be more likely caused by the “sum total of your life experiences,” according to Rosin. A 2010 study in the British Medical Journal found that in those who developed throat cancers, a third had HPV antibodies (meaning they had been exposed to the virus) up to 12 years before the onset of disease.

How can one prevent or lower the chances of getting HPV-related cancers?
Talk to your doctor about getting vaccinated against the high-risk strains of HPV, reduce intake of alcohol and tobacco, limit your number of sexual partners, get tested for HPV if you have any symptoms or concerns. Women should get Pap smear tests of their cervix, which can show abnormal cellular changes that point to a possible HPV infection.

How prevalent is the oral HPV virus in the general population?
A recent snapshot-in-time U.S. study published in the Journal of the American Medical Association found that about seven per cent of Americans aged 14 to 69 are infected by HPV. But only one per cent of the 5,500 people in the study had HPV-16, the most strongly linked strain to oral and cervical cancers. If the figure is extrapolated to the whole population, it would mean that millions have HPV, but fewer than 15,000 Americans develop HPV-linked throat cancers each year. Lead author Dr. Maura Gillison, of Ohio State University, said that should be seen as reassuring; most people with oral HPV don’t get throat cancer.

The same study found that oral HPV infection was more common in men (10 per cent) than women (four per cent). HPV infection was most common in people aged 55 to 59.

How common is oral sex?
The Canadian Youth, Sexual Health and HIV/AIDS study, along with other studies and surveys in the U.S. and Canada, have shown that oral sex is enjoyed by two-thirds of adults. Results have shown it’s increasingly popular among Canadian teenagers. In 1994, nearly half of Grade 11 students (47.5 per cent) reported having oral sex at least once. When the survey was repeated in the same age group in 2002, more than half (52.5 per cent) indicated they had done so.

Should you swear off oral sex?
Since there is a long latency period for HPV infections to inflict serious damage, it’s unlikely there’s any benefit for adults to change sexual practices and preferences, especially if they are in monogamous relationships. But Rosin and Hay agree it may be prudent for individuals to be discriminating when it comes to sexual partners. They can consider asking partners about whether they’ve had HPV, if they’ve been vaccinated against HPV, or about their health and sexual histories.